The present invention generally relates to methods and devices for monitoring electric power systems.
Increasing concerns about the environmental impact of electricity production have led to increased, but dispersed, penetration of renewable energy sources into the power grid. Many of these renewable energy sources are installed at the distribution level of the power grid. The stochastic nature of renewable energy sources, such as solar and wind, and the lack of visibility of the power generated by these sources negatively affect power system operators' situational awareness. In other words, due to the lack of continuous, fast, and accurate monitoring of these renewable energy sources, the power system operators' ability to interpret the present operation state and forecast the upcoming operation state of the power grid becomes problematic. Additionally, renewable energy sources are usually coupled to the power grid via power converters, which tend to affect the power quality of the power grid. As the power quality worsens, the power grid may get less stable and some customer loads may be damaged.
A phasor measurement unit (PMU) is an example of a situational awareness tool capable of providing real-time, global positioning system (GPS) time-synchronized measurements of power grid. However, traditional PMUs are installed at the transmission level, at high voltage substations, and provide limited measurements such as voltage, current, frequency, and phase angle. Moreover, traditional PMUs do not provide information about the quality of the power being transmitted.
Therefore, the inventors recognized a need in the art for accurately monitoring power at the distribution level.